================================================================================
FAQ or Answers to Frequently Asked Questions Section 16
--------------------------------------------------------------------------------
This is a file containing answers, tips, hints and guidelines associated
with recurring questions asked by photographers. If you would like to
add a tidbit of knowledge to this list just send it to ANDPPH@rit.edu
who will gladly add it to this collection.
These files are available in SECTIONS.
This is Section 16 and its contents are listed below.
16.01 -< More Model Releases >-
16.02 -< Pinout Layout for Kodak Projector's remote control >-
16.03 -< PINHOLE Photography Book List >-
16.04 -< Reciprocity Failure - Folk and Real Description >-
16.05 -< Toners - home made stuff >-
16.06 -< Thermography = Infrared Photography of Hot Objects >-
16.07 -< Reverse Text Slides on Vericolor Slide Film >-
16.08 -< Flange to Film Distances for Photo Hackers >-
16.09 -< EV or Exposure Values Explained >-
16.10 -< How to process with Rodinal >-
16.11 -< Processing B&W Film in various developers >-
16.12 -< Making Polycontrast Filters with CC filtration >-
16.13 -< How to use Direct Positive Film >-
================================================================================
Note 16.01 -< More Model Releases >-
--------------------------------------------------------------------------------
Always get the release before the shoot. At that point the model is more
willing to sign. If he/she will not sign or is troubled by any of
the wording a compromise can be reached. Modifications can be made to
the release, just draw a line through the offending sentance/paragraph,
both parties initial by the correction and all is legal.
Some releases, like the one in question, most of the ASMP releases and
many others are very wordy. They may frighten simple folk like you or
me. The release shown below is from a very good book on the business
of photography. It is good but with an emphasis on simple. The book
is "Big Bucks," by Cliff Hollenbeck. Cliff is a travel/location/and
advertising photographer located in Seattle Washington. He is well
known in the business and is an ASMP member. He has been included in 3
"day in the life" books. His Release...
PHOTO RELEASE
I give (your name) permission to photograph myself and/or property,
and to use or sell the materials as he/she whishes.
_______________________________________
Signed
_______________________________________
Name (Print)
_______________________________________
Address
_______________________________________
City State
_______________________________________
Zip Code Date
MINOR PHOTO RELEASE
I give (Your Name) permission to photograph
the below named minor, and to use or sell the materials as he/she
wishes.
__________________________________________
Signed
(Parent/Guardian)
__________________________________________
Minor's Name Age
__________________________________________
Address
__________________________________________
City State
__________________________________________
Zip Code Date
================================================================================
Note 16.02 -< Pinout Layout for Kodak Projector's remote control >-
--------------------------------------------------------------------------------
I seem to recall that from time to time somebody asks for the pinout layout of
Kodak Carousel and Ektagraphic, etc. projectors. I happened to be looking in
some old files and noticed I had a copy of a couple of pamphlets by Kodak that
give this information. The Forward/Reverse functions are quite easy to deal with
since they consist of nothing more than a momentary switch closure. The focus
control is apparently a bit trickier since it involves the use of at least one
diode. It can also be done with two diodes and this is what I will describe
below since it is easier to do in ASCII.
___________ .___________________________.
| | | |
| | | .---|<---*
| | | | |
| forward | | v |
| O O .---*==||===== |
v | || ^ |
=====-----------O-----------* || | | focus
^ | || ---|---
| O O | ||
| | | | || .--------.
| reverse | | | || v |
|_________| | ---*==||===== |
| ^ |
|________________|________|
This looks like a DPDT
switch with Center OFF
This was described in two pamphlets that may or may no longer be available from
Kodak's 800 number. They are Pamphlet Number S-80-4, Kodak AV Equipment Memo
and 70-7, Kodak Slide Projector Wiring and Operation. If these are no longer
available from Kodak you can drop in at my office in bldg. 7B-2244 and ask for
a copy.
andy
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Note 16.03 -< PINHOLE Photography Book List ^-
--------------------------------------------------------------------------------
I would recommend the following books and article on Pinhole Photography:
"The Visionary Pinhole" by Lauren SMITH, Salt Lake City, 1985, Gibbs
M. Smith, Inc., Peregrine Smith Books.
A history of pinhole cameras, beautiful black and white
photographs, with examples of various types of cameras.
It cost $14.95 when I bought it a few years at the
San Diego Museum of Photography
"The Hole Thing: A Manual of Pinhole Fotografy(sic) by Jim SHULL,
Morgan & Morgan, Inc, Publishers, Dobbs Ferry, New York
"The" how-to-do-it-yourself book. Paperback full of useful
illustrated information, with some black and white photographs.
Probably "the" book.
"The International Pinhle Photography Exhibition"
Published by the Center for Contemporary Arts of Santa
Fe, a book full black and white and color photographs
from 22 photographers.
"Pinhole Journal"
Used to be published three times a year, by the
Pinhole Resource, San Lorenzo NM te. 505 536 9942.
A journal devoted to the theory and practice of
pinhole photography--I don't know if it is still
published.
Popular Photography, January 1988, Volume 95, No. 1 had
an extensive article on the subject with good practical tips
on how to get started, how to make the pinholes, etc.
The small "KodaK camera with 126mm film was actually made (I think)
by Time-Filed Co, Newark, Delaware 19711 and called the PinZip 126
and used Kodak Instamatic Cartridge, Kodacolor II, Kodachrome 64,
and Verichrome Pan. It cost $11.95 in 1987 and was available then
through the Pinhole Resource. Again, I don't know the current status
of the camera, or Pinhole Resource. If it is still around, that is
probably the best source of information on the subject.
++++++++++++++++++++++++
CUMMINGSR@RFERL.ORG
RFE/RL Inc
Munich,Germany
================================================================================
Note 16.04 -< Reciprocity Failure - Folk and Real Description -
--------------------------------------------------------------------------------
From: andpph@ritvax.isc.rit.edu
Organization: Rochester Institute of Technology
In article <1993Jun6.110439.6473@adobe.com, wtyler@adobe.com (William Tyler) wri
tes:
>In article >a question for all you photo pros out there... could anyone please explain to
>>me what reciprocity failure is exactly, and how it affects exposure times?
....
The reciprocity law states something to the effect that for a given light level
you achieve the same exposure by using a short exposure time and a large
aperture or a long exposure time and a correspondingly small aperture. While
this law does not fail, the photographic emulsions do in terms of giving the
same density for the same exposure if the exposure time varies widely.
An analogy I sometimes use, rightly or wrongly, is that film is sort of like a
bucket that becomes filled as you pour water into it. Proper exposure is
accomplished under any condition that fills the bucket to the brim. Not enough
is underexposure and too much overflows and is overexposure.
If you have a second bucket of the same volume as the first and you pour its
contents into the first one you would assume that you could fill the first
bucket exactly to the brim (and achieve proper "exposure") automatically since
they are of the same volume. The problem is that you can transfer the contents
pouring a small stream over a long period of time or dumping the contents from
one to the other quickly.
Unfortunately the situation is complicated by the fact thatthat the first
bucket happens to have a very small hole in it and if you take too long to
transfer the contents by the time you are done you will find that you have not
quite filled the first bucket but must add an additional amount of water to
reach the brim. This situation gets worse as the time increases.
At the other end, if you try to transfer the water quickly you are bound to
splash a considerable amount and this will again fail to bring the level to the
desired condition. You need to add an additional amount of water (or exposure
or light) again.
Obviously, over a certain range of transfer times one can quite accurately
transfer the contents of one bucket to the other with no major problem. I guess
it would depend somewhat on the size of the leak and the design of the bucket.
There must be an analogy to film I suppose.
There is an additional factor associated with reciprocity law failure of
emulsions (and just about anything else) and that is the effect on contrast.
This means that areas exposed to different light levels for the same time
produce different photographic effects (or density) than you would expect if
the reciprocity law held true. For this reason there is a development
compensation that is usually made to bring the contrast of the negative to some
predetermined level.
Getting back to the bucket analogy I suppose that to visualize this effect you
would have a series of different volume buckets to fill in the same time and
finally you would be looking at the percent-full value in each bucket to
determine overall contrast.
Anyway, this is only partially worked out and comments, additions, criticisms,
etc. would be appreciated.
Andy
............................................................................
..
and now a more scientific explanantion....
From: francis@.cs.adelaide.edu.au (Francis Vaughan)
Organization: Adelaide Univerity, Computer Science
In article Re: John's inquiry about film available which could be used to photograph a
>building, and the resulting image could possibly indicate areas of heat loss.
John, unfortunately this can not be done with film. While heat-loss is certainly
an infrared effect the temperatures are much cooler than those to which
photographic materials can be sensitized. The most sensitive IR films only
respond to temperatures just below visual red hot. Something like an iron set
to its highest setting.
An indicator of the trouble one would have if, in fact, you could sensitize
film to ambient temperatures is the fact that your own body is hotter than most
buildings. This means that you would be exposing the film by the mere action of
handling the casette while loading the camera.
The kind of instrument that is used to display "thermal infrared", that is
temperatures in the vicinity of body heat, was widely used in the Gulf War.
There they detected in pitch dark conditions the location of tanks whose
engines still retained some heat or soldiers or any activity on the ground that
generated heat beyond that normally present on the desert floor.
These "thermographic" cameras typically compare the temperature of an image
point against a reference temperature provided by liquid nitrogen. One way to
do this is to place a thermocouple at the image and another in the nitrogen.
The slight temperature differential produces a current which can be measured
and displayed on a TV screen as a particular brightness level.
If you have a thremocouple that responds quickly you then move the image of a
scene over the thermocouple using rotating mirrors. You "scan" the image in
fact by having one mirror move the image from side to side and the other move
the image downwards. They are synchronized so that the sideways mirror spins
maybe 50 times faster than the downwards mirror. This gives you 50 vertical
lines of resolution for each picture. Horizontal resolution will depend on how
fast the thermocouple can respond to temperature changes.
The scanning action of the mirrors is also synchronized to the electron gun
deflectors and the electron beam scans the CRT screen from side to side and
downwards at the same timeas the mirrors move the image past the temperature
sensing thermocouple. A thermal picture is thus displayed on the screen. These
days this can be done at 30 pps and pseudo color can be added by electronic
manipulation of the grey levels. In fact, colors can be assigned to grey levels
such that small ranges in temperature are keyed a particular color on the
screen making quantitative analysis of a scene quite easy.
You point a camera like this at a building and hot areas can be made to look
red while cool areas are made blue and heat loss is easily detected. If you
lean up against a wall and then leave these cameras can detect the fact that
someone leaned up against the wall for a considerable time after the thermal
imprint was made. They are useful most anywhere that temperatures need to be
mesured and displayed in a non-contact fashion and over a large area
simultaneously.
Unfortunately the least expensive camera that can do this costs about $ 20,000.
One US manufacturer is Inframetrics. Hughes and Eastman Kodak are others.
Barnes Engineering in England and AG "something" in Sweden (I think) are others.
It is interesting to note that the lenses in these cameras are opaque to the
light that we see. They look like polished black glass. Some of the newer
cameras do not require liquid nitrogen and produce their own reference
temperature somehow. There may be some cameras around that do not use rotating
mirrors but rotating mirrors were the basis on which the industry developed.
Well, I hope this is a start anyway. I may have oversimplified some things but
believe this roughly describes the process of imaging by thermal infrared.
Andy
================================================================================
Note 16.07 -< Reverse Text Slides on Vericolor Slide Film -
--------------------------------------------------------------------------------
From: RSPEIRS@130.187.198.34 (RON SPEIRS)
Subject: Re: White on Blue from Black on White
Organization: Evans & Sutherland Computer Corp.
I need to make some white on blue slides from black on white originals.
How do I go about doing this using Kodak 5072 film?
The following is taken from Kodak Publication E-24,
"KODAK VERICOLOR Slide and Print Films":
-------------------------------------------------------------------------------
"Making Reverse-Text Slides
You can use KODAK VERICOLOR Slide Film to produce reverse-text slides with
white or near white letters on a dark or colored background. To make a
reverse-text slide, photograph dark letters on a white background with color
compensating filters over the lens. For backgrounds of various colors, use
the filters and exposures given in the tables below.
Use a 3200 K light source. To determine the shutter speed and lens aperture
for exposure, use an incident light meter set at the exposure index indicated
below. When you add the filters in front of the camera lens, increase the
exposure as shown in the tables. Make an exposure series of at least +-1
stop in 1/2 stop increments. Keep the exposure time between 1 and 8 seconds.
Note: Reverse-text slides exposed with KODAK WRATTEN Gelatin filters usually
have more saturated colors than slides made with KODAK Color Compensating
Filters.
Using Color Compensating Filters
Use an exposure index of 2 with a filter pack of CP60R + CP50Y over the light
source. Place the color compensating filters over the lens.
Background KODAK Color Increase
Color Compensating Aperture by
in Slide Filter (f-stops)*
Magenta 75G 1
Blue 50R + 50Y 1.5
Cyan 70R + 05Y 0
Dark Green 50M 1
Yellow-Orange 90B + 40C 2
Dark red Remove the CP filter 0
pack from the light
source. Add 90C +
20G in front of the lens.
Using KODAK WRATTEN Gelatin Filters
Use an exposure index of 8 with no filters over the light source. Place the
KODAK WRATTEN Gelatin Filter over the lens.
Background KODAK WRATTEN Increase
Color Gelatine Filter No. Aperture by
in Slide (f-stops)*
Red-brown None 0
Purple 12 (deep yellow) 2
Dark blue 12 + 106 (amber) 2
Cyan 29 (deep red tricolor) 4
Dark green 34A (violet) 4
Red 38A (blue) 4
Orange 44 (light blue-green) 4
Dark yellow 47 (blue tricolor) 4
Magenta 61(deep green tricolor) 5
*You can increase exposure by extending the exposure time, as long as it does
not exceed 8 seconds.
-----------------------------------------------------------------------------
When I use this film in this manner, I use the settings for Compensating
filters from the first table, and dial them into my color head which I
use as the light source. Ron
================================================================================
Note 16.08 -< Flange to Film Distances for Photo Hackers -
--------------------------------------------------------------------------------
FLANGE TO FILM DISTANCES and ADAPTERS
Re: adapting SLR lenses to Leica or to each other is possible by coupling
preferably metal body caps to metal rear lens caps. I would steer clear of
plastic caps as the chance of dropping the lens is substantially greater.
It helps to know what the flange to film distances are in order to make the
adapter the right thickness. I saved a list of lens flange to film distances
for various camera bodies (pre AF) and have listed some below in case you might
find this info useful.
Leica (screw) 28.8 mm Leica (M bayonet) 27.8 mm
Canon (screw) 28.8 mm Canon (FD and earlier) 42.1 mm
Nikon 46.5 mm Minolta 43.5 mm
Pentax K 45.5 mm Exacta 44.7 mm
Alpa Bayonet 37.8 mm Contarex 46.0 mm
Contax RTS 45.5 mm Ikarex BM 44.7 mm
Konica Autoreflex 40.5 mm Miranda 31.5 mm (41.5 mm?)
Olympus OM 46.0 mm Praktica/Pentax * 45.5 mm
Petri Bayonet 45.5 mm Ricoh Bayonet 45.5 mm
Rollei 35 44.7 mm Topcon DM 44.7 mm
Voigtlander 44.7 mm Yashika FR, FX 45.5 mm
* also Alpa 2000 Si, Argus, Chinon, Contax D and S, Cosina, Edixa, Fujica, GAF,
Ikarex TM, Mamiya?sekor, Petri, Pentacon, Ricoh, Spiraflex, Vivitar, and
Yashica SLRs with M42 Universal mount.
Happy hacking and glueing and shooting! I made adapters to fit Canon to Leica
(although Canon makes one of these) and Nikon to Canon and Minolta to Canon
and they're great. I've also adapted Fuji and Miranda lenses to Canon.
andy
================================================================================
Note 16.09 -< EV or Exposure Values Explained -
--------------------------------------------------------------------------------
EV or EXPOSURE VALUES
Can you tell me, what the EV means and how to calculate it? Thanks
EV is a shorthand for a range of shutterspeed/aperture combinations.
EV=0 is 1 sec. at f/1. (If I'm off on this starting point, sorry!)
so 1 sec at f/2 is EV=2, but so is 1/2 sec at f/1.4, but so is
1/4 sec at f/1.
This may seem confusing, but it is convenient for some combinations
of light meters & cameras. Once the meter tells you an EV, then
the camera allows you to set a wide range of shutter speed/aperture
combinations using the EV number as a reference.
This was more common in the 1950's (40's? 60's too?) when cameras
were equipped with an EV scale that coupled the shutter speed lever
with the aperture. You may still find the feature on equipment oriented
to professional use. In recent years, some people/organizations have
keyed a specific EV to a specific combination of film ISO/lighting
intensity. EV then provides a reference to lighting intensity. But the
historic use of EV was just a shorthand notation for a range of
equivalent shutter/aperture combinations.
From: monson@gunarh.ECE.ORST.EDU (Tyrus Monson)
Subject: Re: Exprosure Values ?
Organization: Oregon State University, Corvallis
================================================================================
Note 16.10 -< How to process with Rodinal -
--------------------------------------------------------------------------------
RODINAL
Dilutions and uses of Rodinol
>Hi phorum pholks! Do any of you use Rodinol? I have just bought by
>first jar of it and used it once at 1:50 to develop some T-Max 120. I
>am now shooting Agfa 50asa 120.
I use Rodinal on a regular basis but have found that my negatives tend to be of
lower contrast than I like them when I have followed Agfa's recommendations.
These are some times that were developed and used in the Industrial Photography
area many years ago. Your own individual conditions may dictate modifications to
these suggested times and dilutions and effective speeds. Development is at 68
degrees with agitation every minute.
Light Subject
TRI-X Intensity Contrast ISO Dilution Time
Bright High 250 1:85 14 min
Bright Moderate 400 1:75 14.5 min
Bright Low 400 1:50 14.5 min
Dim High 600 1:75 15.5 min
Dim Moderate 800 1:50 16.5 min
Very Dim High 1200 1:65 17.5 min
Very Dim Low 1600 1:50 18.5 min
Very Dim High 3200 1:65 20 min
Very Dim Low 6400 1:50 22.5 min
Available Light Moderate 800 1:100 17.5 min
PLUS-X
Bright Highest 80 1:100 10.5 min
Bright High 125 1:100 11.5 min
Bright Moderate 160 1:75 11.5 min
Bright Low 400 1:50 12 min
Dim High 400 1:75 12.5 min
Dim Moderate 400 1:50 13.5 min
Dim Low 600 1:50 14.5 min
Very Dim High 800 1:75 15.5 min
Very Dim Low 800 1:50 16.5 min
Normal Moderate 200 1:85 12 min
Panatomic-X (no longer available)(so this should tell you a bit about the time
that these tables were compiled!)
ISO 32
Dilution: 1:100
High Contrast: 18 min
Normal Contrast: 16 min
Low Contrast: 14 min
Date: 30 Apr 1992 15:57:12 -0400
From: ANDPPH@ritvax
Subject: RE: Dilutions and uses of Rodinol
______________________________________________________________________
and here is another suggestion on how to deal with Rodinal...
Subj: Dilutions and Uses of Rodinal
Re: Note 16.10.
I, too, used to find a lack of contrast with Rodinal but I cured it
by doing the following:
7 ml Rodinal
495 ml water
1.3 grams hydroquinone (one level capful from plastic 35mm
film can.)
Hydroquinone, the zippy ingredient in common M-Q developers, will
boost your contrast. It's pretty cheap and can be had in one pound
quantities. Ask your friendly photo store to get it for you---they
probably don't stock it.
Do one roll in a two reel tank. For two rolls, double quantities and
use a four reel tank. Agitate 1st minute then 10 sec/min.
I go 15 mins. at 70 degrees F for Tri-X. Don't know about T-Max
time/temp. If your shadow detail is ok but highlight areas of the
film needs more density you could just use what you've been using
and add the hydroquinone.
This time is for Texas tap water and my cold light enlarger with
"normal" contrast paper. May or may not be appropriate for someone
else but the hydroquinone principle will still be valid.
Hope this helps.
Joe Walsh
Department of Photography
Amarillo (TX) College
================================================================================
Note 16.11 -< Processing B&W Film in various developers -
--------------------------------------------------------------------------------
DEVELOPING BLACK AND WHITE FILMS
Sender: koller@bolzano (Michael Koller)
Organization: ETH Zuerich
I enjoy developping and enlarging my films myself, and so decided to look for
the developping times in different developpers. Here my results: All at 20C.
Shaking every minute for 10 Sec.
Film Perceptol 1:1 ID 11 T-MAX 1:4
(Ilford) (D 76)
Agfa APX 25 12 (25ASA) 7 5,5
Agfa APX 100 11 (50ASA) 7,5 6
Agfa AP 400 14 (200ASA) -- 8
Ilford FP4 + 14 (64ASA) 8 4,5(250ASA)
Ilford HP5 + 15 (200ASA) 7 7
Ilfor Delta 10,5(200ASA) 6(400ASA) 5,5(400ASA)
Kodak TMX -- 9,5 8
Kodak TMY 14(250ASA) 8,5 7
Kodak TMZ 15(1000ASA) -- --
Fuji Neopan 400 -- 7,5 6,5
Fuji Neopan 1600 8,5(800ASA) 7,5 4,5
For Pushing Neopan 1600 resp. TMZ see the Information for the fims which you
get buying them. Two Films which give very good results in Perceptol(conz.) are
Kodak TMX Percept.: 10 Min.
Fuji Neopan 400 Percept.: 11 Min.
The time for this two films in 1:1 is too long .
================================================================================
Note 16.12 -< Making Polycontrast Filters with CC filtration -
--------------------------------------------------------------------------------
CC EQUIVALENTS OF POLYCONTRAST FILTERS
The following are the Ilford filter values for Multigrade.
Grade Kodak Durst
Y M Y M
--- --- --- ---
0 150 25 92 16
.5 110 33 74 22
1 85 42 56 28
1.5 70 55 46 37
2 55 70 36 46
2.5 42 80 28 53
3 30 90 26 60
3.5 18 112 12 75
4 6 135 4 90
4.4 0 195 0 135
5 Not available on these heads.
There are settings for single filters but the advantage of the above is that
the exposure time stays constant i.e exposure for 0-3.5 is rhe same
4-5 is double.
So you should make your initial testsat,say grade 3 and set the filters
accordingly. Then if you need to come down you can use the same exposure time
if you need to go up just double it
Further to the recent correspondence on this subject I have come
across the following figures from a suppliers literature:-
Durst Values
------------
G1 66Y 15M
G2 39Y 33M
G3 20Y 60M
G4 10Y 100M
G5 0Y 178M
* William O`Brien
* E-MAIL OBRIEN@UK.AC.UCCA
================================================================================
Note 16.13 -< How to use Direct Positive Film -
--------------------------------------------------------------------------------
DIRECT POSITIVE FILM
The Kodak Catalog Number for the Direct Positive Developing Outfit
for Tech Pan and T-Max films is Cat No 812 1188
From: IN%"rspeirs@javelin.sim.es.com" 8-SEP-1992 12:48:17.25
Subj: RE: Reversal Processing of T-Max film
>If you have a favorite recipe and instructions on how to process T-Max films to
>achieve superior B&W transparencies I would very much appreciate it if you
>could share this with me and the network assuming that this subject has not
>been worked to death in the last few months that I've been away from here.
There are several B&W films which can be processed to yield positives
Besides the now discontinued Panatomic-X, two other thin-film emulsion films
should work as well: Ilford Pan F and Agfapan 25.
Kodak Technical Pan and T-Max 100 will also work with the appropriate
developer. Following are recipes for 4 developers and other solutions.
The first two, Kodak D-67 and Z-7 were for use with the old Panatomic-X
film, and should be used for the Ilford Pan F and Agfapan. The next two are
formulated to provide good results with Tech Pan and T-Max respectively.
As far as the other solutions go, I cannot explain the differences in
the formulas. Since the bleach and second developer reactions go to
completion, I really don't think that the different formulas would make
much difference. I would discourage the use of Sulfuric Acid in the bleach
because it is hazardous and hard for a private person to obtain. The
Sodium Bisulfate works just as well. Also, I wouldn't bother with the
FD-70a fogging redeveloper; it only lasts an hour once mixed and light
reversal is easy enough and much cheaper.
FIRST DEVELOPER
Kodak D67 Z-7 Tech Pan T-Max
Metol (Elon) 2.0 g 4.0 g 2.0 g
Phenidone 0.25 g
Sodium Sulfite 90 g 34 g 25 g 100 g
Hydroquinone 8 g 5.6 g 5.0 g 5.0 g
Sodium Carbonate Mono 52 g 36 g 30 g 60 g
Potassium Bromide 5 g 1.6 g 2.0 g 4.0 g
Benzotriazole 0.25 g .03 g
Sodium Thiosulfate Penta 16 g
Sodium Thiocyanate 51% 3.0 mL 4.0 mL 3.0 mL
Potassium Iodide 0.1% 10 mL
Water to make 1 L 1 L 1 L 1 L
Time 8 min 6 min 10 min 10 min
Temperature F 68 68 75 68
BLEACH
Potassium Dichromate 9.5 g 11 g 9.5 g 9.5 g
Sodium Bisulfate 22.9 g 66 g
Sulfuric Acid 12 mL 12 mL
Water to make 1 L 1 L 1 L 1 L
CLEAR BATH
Sodium Sulfite 90 g 34 g 90 g 50 g
Water to make 1 L 1 L 1 L 1 L
SECOND DEVELOPER
FD-70a Same as D-19 Dektol 1:2
First Dev
without
Thiocyanate
FIXER F-5 or Usual F-5 Usual film
F-6 Film Fixer Fixer
Processing Schedule
First Developer See times under formulas
Rinse 2 minutes
Bleach 2-3 minutes
Rinse 1 minute
Clear Bath 1.5-2 minutes
Rinse 1-2 minutes
Re-exposure 30-60 seconds each side
Second Developer 3-4 minutes
Rinse 30-60 seconds
Fixer Normal time for fixer used
Wash Appropriate time for fixer used, 10-20 minutes
Photo-flo Wash
Dry
___________________________________________________________________
Agitation in the solutions should be 5 seconds of every 30 seconds.
After the bleach step, re-exposure to light renders the remaining silver
developable. The use of stainless steel or clear plastic processing reels
makes it possible to re-expose the film while on the reel. Optimum re-exposure
is about 800 foot-candle seconds, but the amount of re-exposure is not
critical. Both sides of the reel should be exposed for 30-60 seconds to a 60
or 75 watt bulb at 12 to 18 inches. The reel should be rotated constantly
during re-exposure. A 30 to 40 second exposure to a 40 watt fluorescent tube
at 2 to 4 inches can also be used. No variation in density will be apparent
until these exposure values are changed to about 1/10 or 10 times the
given amounts.
As can be seen from the formulas, the steps following the first developer
are not too critical; although the clear bath should not exceed 2 minutes.
Also, room light is OK after the bleach step. Typically you would expose
Ilford Pan F or Agfapan 25 at about twice their ISO speeds. My source for
T-Max 100 indicates that it can be used at its negative rated speed of ISO 100.
The Tech Pan should be rated at ISO 40. My sources also indicate that
D-67 can be made by adding 3 mL of Sodium Thiocyanate 51% to D-19 developer.
If anyone decides to try these formulas, be sure to shoot a test roll first
and bracket to find optimum exposure. Since you will get a positive, follow
the exposure rules as for color slide film: More exposure = lighter, less
dense image; less exposure = darker, denser image.
----------------------------------------------------------------------------------
PhotoForum (Internet)
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listserv@listserver.isc.rit.edu
with this text in the BODY of the mail:
subscribe photoforum your-name-here
where it says your-name-here substitute your real name and then send message.
Also, there are a number of articles available from this server. Get to them
at the following URL: http://www.rit.edu/~andpph/articles.html
For info on a global databank of schools offering photography instruction go
to: http://www.rit.edu/~andpph/database.html
FTP: You can also obtain most of these files also by Anonymous FTP from
vmsftp.rit.edu under pub/ritphoto/photoforum
WWW: You can access the PhotoForum Home Page on the WWW at the this address:
http://www.rit.edu/photoforum
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![[PhotoForum logo]](http://www.rit.edu/~andpph/pf-logo.jpg){kind=logo}